EN: Graphite tables
Graphite is an extension to TrueType which embeds several tables into a font containing rules for contextual shaping, ligatures, reordering, split glyphs, bidirectionality, stacking diacritics, complex positioning, etc.This sounds rather like OpenType -- except that OpenType depends on the text layout routines knowing a lot about the glyphs involved. This means that OpenType fonts cannot be designed for a new language or script without shipping a new version of the operating system. Whereas Graphite tables contain all that hidden information. Apple s Advanced Typography provides a better comparison, but Graphite tables are supposed to be easier to build. SIL International provides a free Graphite compiler .
Font Forge Glossary